umount(2) SDK R4.11 umount(2)
NAME
umount - remove a file system device
SYNOPSIS
#include <sys/mount.h>
int umount (special)
char * special;
where:
special Address of a pathname
DESCRIPTION
Umount removes the file system device identified by special or
mounted on the file special from the set of active file system
devices with the following consequences:
· The filename store contained on special is removed from the
system filename store. Thus, all files contained on special
can no longer be named.
· The filesystem contained on special is removed from the system
flat file store. Thus, all files contained on special can no
longer be accessed.
· None of the files on special may be open. No process may have
its current working directory on special.
· The filename store contained on special cannot contain a mount
point of any other file system device at the time of the call
to umount.
· Special must have previously been the subject of a successful
mount operation. If umount is successful, the sub-tree over
which special was mounted reappears in the system file name
store. These files can now be named.
· If special refers to a named stream and there are no other
references to the stream, the stream is closed and its
resources deallocated.
If an error occurs, no changes are made.
ACCESS CONTROL
To unmount a dg/ux or nfs file system, the calling process must have
appropriate privilege. To unmount a namefs file system, the calling
process must have appropriate privilege or must be the owner of
special. For systems supporting the DG/UX Capability Option,
appropriate privilege is defined as having one or more specific
capabilities enabled in the effective capability set of the calling
process. See capdefaults(5) for the default capability for this
system call.
On systems without the DG/UX Capability Option, appropriate privilege
means that the process has an effective UID of root. See the
appropriateprivilege(5) man page for more information.
RETURN VALUE
0 Special was successfully unmounted.
-1 An error occurred. errno is set to indicate the error.
DIAGNOSTICS
Errno may be set to one of the following error codes:
EBUSY There are still processes accessing file system
objects on special.
EBUSY A file contained on special is the mount point of
another file system device.
EBUSY special is a memory-resident file system which
contains files and directories which must be removed
prior to unmounting.
EINVAL Special is not mounted.
ENOENT The named file does not exist.
ENOTBLK Special is not a block special file.
ENXIO The device associated with special does not exist.
EIO I/O error when flushing file system information.
EPERM Permission to unmount the file system device is denied
to the calling process.
ENOENT A non-terminal component of the pathname does not
exist.
ENOTDIR A non-terminal component of the pathname was not a
directory or symbolic link.
ENAMETOOLONG The pathname exceeds the length limit for pathnames.
ENAMETOOLONG A component of the pathname exceeds the length limit
for filenames.
ENOMEM There are not enough system resources to resolve the
pathname or to expand a symbolic link.
ELOOP The number of symbolic links encountered during
pathname resolution exceeded MAXSYMLINKS. A symbolic
link cycle is suspected.
EPERM The pathname contains a character not in the allowed
character set.
EFAULT The pathname does not completely reside in the
process's address space or the pathname does not
terminate in the process's address space.
SEE ALSO
mount(1M), dgmount(2), mount(2), fs(4), appropriateprivilege(5).
capdefaults(5).
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